1. Field of the Invention
This invention generally relates to vehicle mounted sensor systems and more particularly to a system for determining characteristics of surface material related to adverse driving conditions from a vehicle.
2. Description of Related Art
A number of attempts have been made to sense the conditions of roadways, aircraft runways, and other surfaces for vehicular traffic, during changing adverse weather conditions For example, it is known to place conductivity, temperature and other sensors either in the road surface or adjacent the road to monitor the temperature of the road surface and/or monitor whether there is ice forming on the surface. This information is fed to the center for control and dispatch of trucks to apply salt or sand or other deicing mixtures. At airports these types of warning systems are used to inform maintenance crews that the runways need to be treated or alert the staff that deicing procedures need to be implemented. Some conventional systems have a supply of chemicals and pumps beside the roadway to automatically spray the road when triggered by a sensor.
There is also a need for such a warning system on road vehicles such as cars and trucks to detect pending adverse conditions. However, available mobile systems are limited to basic moisture detection and temperature monitoring systems. Some examples of such systems are disclosed in U.S. Pat. Nos. 4,492,952 and 4,678,056. One particular system, disclosed in U.S. Pat. No. 5,416,476, employs an infrared sensor which is mounted on the exterior of the vehicle and sends a signal to a microprocessor which then can display the temperature of the road surface. These systems are simplistic and do not tell the operator the critical information needed under all conditions, such as, at what temperature will the particular material actually on the road surface freeze? Therefore there is a need for a material sensing apparatus and system for determining when an actual liquid on a road surface will freeze and alerting the operator to such situations before they actually occur so that the operator can adjust driving techniques accordingly.
There is also a need for a mobile mounted sensing apparatus and system for use by road crews to evaluate existing material on a road surface in order to determine the amount of additional material to be applied to the surface in order to reduce the hazardous driving conditions.